Magaña, Hugo A. 2007. A case for classifying the
Rio Grande silvery minnow (Hybognathus amarus) as an omnivore.
Albuquerque, NM: The University of New Mexico. 109 p. Dissertation.

The Rio Grande has been identified as one of the most endangered
rivers in the United States by American Rivers. Water impoundment,
water extraction, and point-source pollution have likely contributed
to the decline of the federally endangered Rio Grande silvery
minnow (Hybognathus amarus). The overall goal of this
study was to locate, identify, and characterize food resources
for H. amarus and the ichthyofauna of the Middle Rio Grande
(MRG). After locating possible food resources (chapter 1) A single
diatom cell was isolated from a mixed environmental collection
and grown in monoculture. Unialgal cultures were used to assess
H. amarus diatom preferences and conditioning response
(chapter 2). An extended flood-pulse release from Cochiti Reservoir
allowed me to investigate food resource usage during a flood
event. Trophic interactions between fish, aquatic invertebrates,
and periphyton were identified using stable isotope analyses
(?13C and ?15N) and paleolimnology techniques (chapter three).